Here’s a hint: If Betty White tells you your shoelaces are untied, don’t look down. As Betty White’s Off Their Rockers proves, the merry Golden Girl just loves practical jokes – especially when she’s pulling them on her famous friends.

At 5:42 p.m. yesterday evening, White apparently sent out her very first tweet. Her verified account – which has only published three messages so far – quickly accumulated over 100,000 followers. But a certain actress wasn’t so sure that @BettyMWhite was the real deal. At 2:14 p.m. today, White’s Hot in Cleveland costar Valerie Bertinelli sent out an urgent tweet of her own: “Just spoke with Betty and she is VERY upset! @BettyMWhite is NOT her. Don’t know how they got verified, but it is not Betty. Please RT!”

But less than an hour later, Bertinelli started changing her tune. “Stop the presses!” she said at 2:52. “Betty just got a call. An account was opened on her behalf by her people. More to come…” Soon after that, the One Day at a Time actress sent out another sheepish message: “I think @BettyMWhite pranked me but good! #blushing.”

So did White not know that her team had started a Twitter account in her name? Or did Bertinelli get punked by the senior citizen? According to White’s rep, it’s the latter. While White doesn’t send out tweets herself, she does approve everything on her feed – and she’s been doing so since the page went live yesterday. “Betty pranked Valerie,” he confirms.

Now that White’s started pulling fast ones even when she’s off the set of Off Their Rockers, no ’90s sitcom star is safe. What’s next? Will she trick Lisa Kudrow into wearing a Playboy Bunny outfit to a shindig that isn’t a costume party? Is Ben Savage going to discover that his bed has been short-sheeted? Will White start endorsing the left-handed Whopper? Leave the prankster some ideas in the comments – then check out the ceiling. I’m pretty sure someone painted “gullible” up there.